Air-cooled engine

Abstract

An air-cooled engine capable of enhancing detection precision of a temperature sensor includes a crankcase, a crankshaft, a fan case, and an engine cooling fan. The installation direction of the crankshaft defines the front and rear direction. The fan case is provided in a front part of the crankcase, and the engine cooling fan is accommodated in the fan case. The air-cooled engine includes a cooling wind passage, a wind passage terminal end wall, an oil splashing device, and a temperature sensor. The wind passage terminal end wall is provided in a rear end of the cooling wind passage, the oil splashing device is provided on the rear side of the wind passage terminal end wall and formed to splash engine oil in the crankcase onto the wind passage terminal end wall, and the temperature sensor is attached to a front part of the wind passage terminal end wall.

What is claimed is: 
     
       1. An air-cooled engine comprising:
 a crankcase; 
 a crankshaft; 
 a fan case; and 
 an engine cooling fan, wherein 
 with the installation direction of the crankshaft serving as the front and rear direction, one side of the front and rear direction serving as the front side, and the other side serving as the rear side, the fan case is provided in a front part of the crankcase, and the engine cooling fan is accommodated in the fan case, 
 the air-cooled engine comprising: 
 a temperature sensor and an oil splashing device, the temperature sensor being attached to a front part of a cooling air passage terminal end wall and coordinated with a fuel supply device adjusting an amount of a fuel supply via an electronic control device, and the oil splashing device splashing engine oil in the crankcase onto the cooling air passage terminal end wall to which the temperature sensor is attached. 
 
     
     
       2. The air-cooled engine according to  claim 1 , comprising:
 a sensor attachment boss; and 
 a sensor attachment bolt, wherein 
 the sensor attachment boss is provided in the wind passage terminal end wall, a rear part of the sensor attachment boss projects rearward from the wind passage terminal end wall, the sensor attachment bolt is screwed into the sensor attachment boss, and the temperature sensor is attached to the sensor attachment boss by the sensor attachment bolt. 
 
     
     
       3. The air-cooled engine according to  claim 2 , comprising:
 an oil guiding rib, wherein 
 the oil guiding rib projects rearward from the wind passage terminal end wall and is formed to guide the engine oil splashed by the oil splashing device to the rear part of the sensor attachment boss. 
 
     
     
       4. The air-cooled engine according to  claim 1 , wherein
 a timing transmission device is also used as the oil splashing device. 
 
     
     
       5. The air-cooled engine according to  claim 1 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       6. The air-cooled engine according to  claim 5 , comprising:
 a wind shielding plate, wherein 
 the wind shielding plate is provided in an inlet of the cooling wind passage, and the temperature sensor is arranged at a position to be hidden behind the wind shielding plate when seen from the front side in the direction parallel to the installation direction of the crankshaft. 
 
     
     
       7. The air-cooled engine according to  claim 6 , wherein
 cooling wind introduction gaps are provided between the wind shielding plate and circumferential walls of the left and right cylinders. 
 
     
     
       8. The air-cooled engine according to  claim 6 , wherein
 the wind shielding plate includes a top plate part extending in an upper part of the fan case. 
 
     
     
       9. The air-cooled engine according to  claim 8 , wherein
 the top plate part of the wind shielding plate is made of a magnetic material. 
 
     
     
       10. The air-cooled engine according to  claim 1 , wherein the electronic control device is formed to adjust an amount of fuel supplied to a combustion chamber by the fuel supply device based on a temperature detected by the electronic control device via the temperature sensor. 
     
     
       11. The air-cooled engine according to  claim 2 , wherein
 a timing transmission device is also used as the oil splashing device. 
 
     
     
       12. The air-cooled engine according to  claim 3 , wherein
 a timing transmission device is also used as the oil splashing device. 
 
     
     
       13. The air-cooled engine according to  claim 2 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       14. The air-cooled engine according to  claim 3 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       15. The air-cooled engine according to  claim 4 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       16. The air-cooled engine according to  claim 11 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       17. The air-cooled engine according to  claim 12 , comprising:
 left and right cylinders, wherein 
 the left and right cylinders project obliquely upward from the crankcase to form a V shape when seen in the direction parallel to the installation direction of the crankshaft, the cooling wind passage is provided between the left and right cylinders, and the wind passage terminal end wall projects upward from the crankcase. 
 
     
     
       18. The air-cooled engine according to  claim 13 , comprising:
 a wind shielding plate, wherein 
 the wind shielding plate is provided in an inlet of the cooling wind passage, and the temperature sensor is arranged at a position to be hidden behind the wind shielding plate when seen from the front side in the direction parallel to the installation direction of the crankshaft. 
 
     
     
       19. The air-cooled engine according to  claim 14 , comprising:
 a wind shielding plate, wherein 
 the wind shielding plate is provided in an inlet of the cooling wind passage, and the temperature sensor is arranged at a position to be hidden behind the wind shielding plate when seen from the front side in the direction parallel to the installation direction of the crankshaft. 
 
     
     
       20. The air-cooled engine according to  claim 15 , comprising:
 a wind shielding plate, wherein 
 the wind shielding plate is provided in an inlet of the cooling wind passage, and the temperature sensor is arranged at a position to be hidden behind the wind shielding plate when seen from the front side in the direction parallel to the installation direction of the crankshaft.